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Old 04-04-2002, 07:26 PM   #1
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Default Esc Capacitors

Is the worlds kit for the quantum competition really necessary. Or what about the TC2. I've noticed that Matt Francis does run the worlds kit. He's sponsored by LRP. What is the purpose of the caps. I've heard different stories. Some say it's to benefit your batteries, other say it's for more punch. Is there an expert in the house?? I'm running into space issues with my cars and caps.
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Old 04-04-2002, 10:37 PM   #2
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ive heard from other quantum owners in our track that adding the capacitors do increase punch. i have a quantum but im not running the worlds kit. i only have the heatsink that i got from a friend. i noticed that the esc definetly runs cooler with the heatsink, but i havent tried one with the capacitor yet. i dont know if the heatsink is available separately from the caps.
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Old 04-05-2002, 01:30 AM   #3
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This has been discussed over and over again on this message board. You may want to have a look at the older threads.
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Old 04-05-2002, 10:40 PM   #4
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the higher the rating for the cap, the faster the car accelerates because it stores more energy and releases more energy and giving the motor faster spool up
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Old 04-06-2002, 12:15 AM   #5
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I have a question about the Quantum's heatsink... From what I saw, it attaches to the case of the speed control with double sided tape? How can this do anything to cool the FETs?

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Old 04-06-2002, 06:13 AM   #6
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my capacitor spec : 16V..... 10,000 mF...... 105 C. Is it big enough for modified racing??
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Old 04-07-2002, 06:18 AM   #7
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trips,

its not double sided tape its heatsinking compound (I think), anyway the FET's are located under the sticker, the heatsink sticks to that bit and takes heat away. as for the Caps. i would use one to stop the darn thing blowing up!

have a nice day

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Old 04-08-2002, 02:09 AM   #8
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Read the earlier discussions...
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Old 04-08-2002, 10:59 AM   #9
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Default Capacitors

Why do we need them? Its because nowadays technology gives us stronger and more reliable batteries and that way motor manufacturer's build motor turns that even goes beyond our imagination like 6 turn motors or so. Capacitors are badly needed to protect the speedos from thermal shutdown in someways. On the otherhand, caps stores current juice and helps the batteries to maintain its power level while in use to keep it cool.
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Old 04-09-2002, 07:59 AM   #10
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Well what I have read so far is incorrect on this thread.

Smaller number/ Smaller Cap = more punch (typically run with a stock motor, you can run 3 in parallel to gain extra punch out of the corner in stock)

Larger number/ Bigger Cap = Smoother power band (typically run with a mod motor, think about it, why do you need more punch with a 8x2?)
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Old 04-09-2002, 12:14 PM   #11
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I guess you know better
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Old 04-11-2002, 08:23 AM   #12
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David Joor, any difference for a 16V or 25V rating cap. when solder to ESC?
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Old 04-11-2002, 08:48 AM   #13
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I believe there is, always use a 16v for consistancy.
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Old 04-11-2002, 10:28 AM   #14
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David Joor: Don't take this personally but your comments are wrong.

If you run capacitors in parrallel you obtain the total capacitance from adding the individual capacitances together so if you run 3 small capacitors in parrallel then it is the same as running 1 larger capacitor.
The capacitor just smooths the current flowing from the batteries to the motor which will result in a cooler speedo as well as more punch and efficiency. A bigger capacitor or several smaller ones is better because the more charge in the capacitor, the harder it is to get more in. The gains get less the further you go with the capacitance though. Generally I don't think it is worth running any higher capacitance than the speedo manufacturer supplies as standard as it will make very little difference and just add weight. The exception is if you are running very low wind modifieds when it may be worth it to protect the speedo from the increased voltage spikes that these motors can produce due to the high rpm and amp draw.

As for 16V versus 25V.
I thought that the only reason capacitors were rated for voltage is because if you take the voltage too high the dielectric decomposes. Higher voltages require thicker or better dielectric but that has an adverse affect on the capacitance so the capacitor has to have a larger plate area if the same dielectirc is used.
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Old 04-11-2002, 10:39 AM   #15
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dw - I am not a EE, my observations are from track experience. Running the three in parellel ads punch to my stock motors, I believe it is due to the capacitors (equalling 1) but holding more current now will release the stored energy at the same time at the same rate but in larger quanity because of 3. Thus in a voltage drop situation such as punch coming out of a turn, it dumps more power into the system. The larger cap on the other hand seems to make my mods run smoother and more effecient.

If I am wrong then I am wrong in theory, but I did testing on this for 2 weeks trying to figure out what it felt like on the track and that was my synopsis.
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